Should Napier have been building the Griffon instead of the Sabre?

[gruad]

Looking at a lot of documentaries on YouTube, it seems very much that Napier worked way outside of what was possible. Whereas Rolls-Royce were able to purpose themselves to make engines that were in the realms of technology.

The tempest/typhoon could have been available much earlier with the Griffon engine. It seemed that Napier enjoyed the technological challenges of the H24 engine without considering the practicalities. Surely the air ministry should have put the stop to this nonsense and just got Napier workers working on something that we know would work such as the Griffon.

It seems like there were two top companies for the RAF: Rolls-Royce and Avro who got things done. Surely the weaker performers should have been subordinated to them?

Post war they went mad too with the Nomad!

 

[SaparotRob]

I am Nomad. I am perfect.

 

[tomo pauk]

The tempest/typhoon could have been available much earlier with the Griffon engine.

How do you figure?

 

[gruad]

How do you figure?

Hmmm hoist by my own petard!

The RR alternative for the Tempest was the Vulture now I find.

Apologies.

 

[gruad]

I am Nomad. I am perfect.

That was the video that triggered this off. How could a company consider such an un simple engine?

 

[SaparotRob]

Boredom.

 

[ThomasP]

Must you sterilize? or exterminate?

 

[wuzak]

Looking at a lot of documentaries on YouTube, it seems very much that Napier worked way outside of what was possible. Whereas Rolls-Royce were able to purpose themselves to make engines that were in the realms of technology.

The tempest/typhoon could have been available much earlier with the Griffon engine. It seemed that Napier enjoyed the technological challenges of the H24 engine without considering the practicalities. Surely the air ministry should have put the stop to this nonsense and just got Napier workers working on something that we know would work such as the Griffon.

It seems like there were two top companies for the RAF: Rolls-Royce and Avro who got things done. Surely the weaker performers should have been subordinated to them?

Post war they went mad too with the Nomad!

I'm not sure that being an H-24 was that much of an issue for the Sabre.

Especially compared to the issues they had with the sleeve valves.

The Griffon engine was not started until 1938, around 3 years after the Vulture and Sabre projects started.

Certainly a Griffon Typhoon would not have been available before 1942, which was after the Typhoon entered service (albeit prematurely).

 

[wuzak]

Hmmm hoist by my own petard!

The RR alternative for the Tempest was the Vulture now I find.

Apologies.

The Vulture was the engine to be used for the Tornado, which was basically the Typhoon with a different engine.

The Tempest was a later development of the Typhoon family with laminar flow wings. The engine choices were the Sabre with leading edge radiators (Mk.I), Sabre with Chin Radiator (Mk.V), Centaurus (Mk.II), Rolls-Royce Griffon IIB but changed to Griffon 85 (Mk.III), and Griffon 61 (Mk.IV) not built.

The Mk.III with Griffon 85 prototype was modified to become one of the Fury prototypes, and ended up being fitted with a late model Sabre.

 

[wuzak]

That was the video that triggered this off. How could a company consider such an un simple engine?

The Nomad 2 was simple....





....compared to the Nomad I.

 

[SaparotRob]

Must you sterilize? or exterminate?

Steeerrr...rrriiillllll...iizzzzzeee........

 

[Shortround6]

With some of these engines it was a question of which engine was promising what (HP or HP at Altitude) when (year-month).

The Griffon and Sabre were both 36.7liter engines.
The Griffon was smaller/lighter but it was limited to 2750rpm. (or RR didn't push it).
The Sabre was larger/heavier and they tried for 3850rpm (or higher?) so with everything being equal ( ) the Sabre should make 40% more power. Assuming the the same fuel and so on. In 1938 the fuel was 87 octane with 100 octane (NOT 100/130) coming in a few years (maybe 1939, maybe 1940???)

Now it turned out that the Sabre, in addition to some of it's well known problems, didn't handle high boost very well, the sleeve valves distorted/broke and the higher boost with better fuel made up some of the difference power between the two engines. But this wasn't until 1942-43.

This is sort of the cliff notes version.

Trying to build(design even on paper) a Typhoon in 1937-38 with Griffon engine using 87 octane fuel would not have come close to giving the performance desired.

 

[gruad]

With some of these engines it was a question of which engine was promising what (HP or HP at Altitude) when (year-month).

The Griffon and Sabre were both 36.7liter engines.
The Griffon was smaller/lighter but it was limited to 2750rpm. (or RR didn't push it).
The Sabre was larger/heavier and they tried for 3850rpm (or higher?) so with everything being equal ( ) the Sabre should make 40% more power. Assuming the the same fuel and so on. In 1938 the fuel was 87 octane with 100 octane (NOT 100/130) coming in a few years (maybe 1939, maybe 1940???)

Now it turned out that the Sabre, in addition to some of it's well known problems, didn't handle high boost very well, the sleeve valves distorted/broke and the higher boost with better fuel made up some of the difference power between the two engines. But this wasn't until 1942-43.

This is sort of the cliff notes version.

Trying to build(design even on paper) a Typhoon in 1937-38 with Griffon engine using 87 octane fuel would not have come close to giving the performance desired.

I guess I didn't factor long development time into my answer. Merlin thus not forced into production= less visible ironing out of bugs?

Apparently vulture version of Tempest promising but too unreliable. So I admit I am applying double standards to RR and Napier.

Again R3350 also Turbo Compound so more double standards. I would guess that Turbo Compound is another possibly simpler way to get exhaust energy than a turbo, but you would still need a supercharger to compress air at high altitude?

 

[wuzak]

Apparently vulture version of Tempest Typhoon promising but too unreliable. So I admit I am applying double standards to RR and Napier.

Vulture reliability wasn't too bad in the Tornado.

It was very poor in the Manchester, though.

 

[z42]

Trying to build(design even on paper) a Typhoon in 1937-38 with Griffon engine using 87 octane fuel would not have come close to giving the performance desired.

In retrospect the mistake was maybe they tried too much. Both the Vulture and the Sabre were big leaps compared to the Merlin, which cost them in terms of being behind schedule and having all kinds of exotic reliability problems. Had the Air Ministry said that as a follow-up to the Merlin they wanted a boring poppet valve V-12 with some 30% more power, and then have the next generation fighter designed around that engine, maybe they could have had something deployed and somewhat reliable by the time the FW 190 showed up.

And yes, that plane would have been smaller than the Typhoon. And sure, have Napier design and build that engine, if the ministry is concerned about avoiding a RR monopoly.

Of course, with highly respected people like Ricardo and Fedden saying the future is sleeve valves, not sure the Ministry could, at the time, go against that and require poppet valves.

 

[tomo pauk]

Of course, with highly respected people like Ricardo and Fedden saying the future is sleeve valves, not sure the Ministry could, at the time, go against that and require poppet valves.

What does RR says?

 

[Shortround6]

What does RR says?

RR was playing with a sleeve valve engine in the mid-late 30s.
May to see if there was anything to it?
It was designed (or team led by ) Arthur Rowledge of Sabre fame (and Condor III, Kestrel, "R" Schneider, and Merlin) But RR stopped with one flying example, but restarted an enlarged version in 1943.

So RR was sort of hedging it's bets.

 

[Shortround6]

In retrospect the mistake was maybe they tried too much. Both the Vulture and the Sabre were big leaps compared to the Merlin, which cost them in terms of being behind schedule and having all kinds of exotic reliability problems. Had the Air Ministry said that as a follow-up to the Merlin they wanted a boring poppet valve V-12 with some 30% more power, and then have the next generation fighter designed around that engine, maybe they could have had something deployed and somewhat reliable by the time the FW 190 showed up.

And yes, that plane would have been smaller than the Typhoon. And sure, have Napier design and build that engine, if the ministry is concerned about avoiding a RR monopoly.

Of course, with highly respected people like Ricardo and Fedden saying the future is sleeve valves, not sure the Ministry could, at the time, go against that and require poppet valves.

Some of this is marketing.
Or matching marketing to demand.

It is one thing for the air ministry to ask for a 1300hp engine in the late 30s.
But since there were already several different 1000hp engines and at least one 1300hp engine already being tested or in production, Having engine maker "C" limit itself to a 1300hp engine when they know that engine makers "A" and "B" are working on 1800-2000hp engines means that "C" would be limiting their future market. Or get squeezed between improved versions of the existing 1000hp engines and the higher powered engines. You need an order for lot of engines to make it worthwhile to tool up.
And again, in 1938 RR KNEW that the Merlin could stand up to 1600-1800hp mechanically. The problem was making it, more rpm or more boost? Or???

It would be interesting to see the progression of the Merlin engine in the design rooms/test rooms in 1938 and 1939. What they were aiming for vs what they knew they could deliver.
The two speed supercharger took a lot the pressure off, except that they could not switch all production over to 2 speed engines.
The Merlin X in 1938 was being advertised at being 21% more powerful for take-off than the Merlin III engine on 87 octane fuel. For several hundred pounds less engine weight than drawing board Griffon.

For Napier to commit themselves to sort of 2nd tier engine would be to doom the future of the company. Turned out the Sabre sort of doomed them anyway but at least they tried.

 

[ThomasP]

If I am not mistaken, the last 3 major piston engine projects taken on by RR were sleeve valve engines - ie the Crecy, Pennine, and Eagle. They obviously thought the sleeve-valve was worth pursuing. The output powers - actually achieved and projected - speak for themselves.

I realize that the idea of sleeve valve vs poppet valve pros & cons has been done before (multiple times on this and other forums), and am not trying to start another.

 

[Shortround6]

Pennine, X-24 configuration. displacement of 2,792 cu in (45.8 L); this was over twice the displacement of the Exe. With a dry weight of 2,850 lb (1,293 kg), The engine was equipped with a single stage, two speed supercharger that provided 12 psi (.83 bar) of boost at takeoff and combat power settings. The Pennine developed 2,750 hp (2,051 kW) at 3,500 rpm at sea-level and up to 2,800 hp (2,088 kW) under combat settings. A reliable 3,000 hp (2,237 kW) was thought to be easily obtainable with further development.

From Rolls-Royce Exe (Boreas) and Pennine Aircraft Engines

Note that the Pennine was 24.6% larger than the Griffon and ran at 3500rpm instead of 2750rpm.
Also note the 12lbs of boost which a Merlin could use in 1940.
The Sleeve valves could not use high boost. Using 24 cylinders allowed for higher rpm.
A single stage Griffon was about 1800lbs (0.5 ton lighter)
The Griffon could not do what the Pennine could do and the cruise power of the Pinnine was probably closer to the peak power.
One does wonder what a 24 cylinder engine using Merlin cylinders would do though